Polonium-217

Properties and data of the isotope ²¹⁷Po.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

See also: List of individual Polonium isotopes (and general data sources).

General data

Name of the isotope:Polonium-217; Po-217Symbol:²¹⁷Po or 21784PoMass number A:217 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:133Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5833333333333 (= neutron-proton ratio)Neutron excess (N-Z):49Isotopic mass:217.006316(7) u (atomic weight of Polonium-217)Nuclide mass:216.9602407 u (calculated nuclear mass without electrons)Mass excess:5.88332 MeVMass defect:1.803420516 u (per nucleus)Nuclear binding energy:1679.87539013 MeV (per nucleus)
7.74136124 MeV (average binding energy per nucleon)Separation energy:S_N = 3.970(7) MeV (first neutron)
S_P = 7.279(13) MeV (first proton)Half-life:1.53(5) sDecay constant λ:0.453037372915 s^-1Specific activity α:1.25726031083 × 10⁺²¹ Bq g^-1
33980008400.919 Ci g^-1Spin and parity:
(nuclear angular momentum)(9/2+)Magnetic dipole moment:μ(μ_N) = -1.106(103)Quadrupole moment Q:0.06 barn (100 fm²)Nuclear g-factor:g_l = -0.24577777777778Year of discovery:1956

Radioactive Decay

Half-life T_½ = 1.53(5) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹³Pb	> 95 %	6.6621(23) MeV
β^-	²¹⁷At	< 5 %	1.489(8) MeV

Parent Nuclides

Direct parent isotopes are: ²²¹Rn, ²¹⁷Bi.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 133) and isobaric (same nucleon number A = 217) with Polonium-217. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 133	Isobar A = 217
80	²¹³Hg
81	²¹⁴Tl	²¹⁷Tl
82	²¹⁵Pb	²¹⁷Pb
83	²¹⁶Bi	²¹⁷Bi
84	²¹⁷Po	²¹⁷Po
85	²¹⁸At	²¹⁷At
86	²¹⁹Rn	²¹⁷Rn
87	²²⁰Fr	²¹⁷Fr
88	²²¹Ra	²¹⁷Ra
89	²²²Ac	²¹⁷Ac
90	²²³Th	²¹⁷Th
91	²²⁴Pa	²¹⁷Pa
92	²²⁵U	²¹⁷U
93	²²⁶Np